Heating system.



No. 851.363. PATENTED APR. 23, 1907. H. c. MALLORY.

HEATING SYSTEM.

APPLIOATIOK FILED HBVJQ, 1908.

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APPLICATION FILED NOV. 24, 1906.

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PATENTED APR. 23, 1907.

H. C- MALLORY. HEATING SYSTEM.

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UNITED STATES i a'lrnufr OFFIGF.

HEATING SYSTEM.

Specification of Letters Patent.

Patented Apri 23, 1907.

Application filed November 2d. 1908. Serial No. 344,821.

To (all u',- in if "my concern:

Be it known that I, HARRY L. MALLORY, a citizen offhd United States ofAmerica. rcsiding' in tll cilj, county, and State of New Yorit, haveinvented a certain new and useful lrnprevement in H ating Systems, of\vliiri'l Lhe following is aciue and exact description, reference beinghad to the aecom panying drawings, which form a part thereof.

My present invention relates to heating systems such as are employed inheating buildings, and has for its object improve; mouts in the meansfor regulatin ill; heating capacit or effect of the heating devices orradiators.

My invention is particularly designed for controlling steam radiators,though it is by no meanslimited in all of its aspects to use with steamradiators but ma be used where hot water or other fluid hes ng agentisemplo "ed.

aim of the features 0? my invention consists in subjecting thethermostatic actuating mechanism employed for controlling the flow ofthe heating fluid through the heating devices to'the action ofa stf m ofa fluid tem perature changing agent which is caused to {lou inst it an.by the thermostatic actu ai ing mechanism, changing the temperature ofthe latter in passing.

Another feature ofimyinvention consists in varying the heatradiatingcap'acity 0T5? heat ra-diatin unit in response to variations inthe extermiil tern eratnre.

A Uaiifl'fit'fif'o invention consists in varying the capacity 0wheat-radiator in response-w variations of the external tempera- 'tureand further varying the capacity of the od izi'l or in response to thetemperature of the a artmcnt to ,be heated.

A ourth feature of my invention consists in drawing the stream of fluidacting thermally on the thermostatic actuating mocham' ism of thecontrol valve into the low prcssure rclurn pipe of the heating system.

Ali of the above enumerated features of my invention are prcscnl in thepreferred form of ap aratus for carrying out no invention in which idraw a stream of air rorn the external atmosphere through a chambercontaining, or in proxiinitytb, the thermostatic actuatin r mechanism ofthe control valve into the ow rcssure return conduit. leading from theradiator and employ 2 'Uermdstfltic pilot valve governed by theTcmpcMToEe. 0%

matter in which I have illustrated an the apartment to be heated forgoverning the flow of said stream of air. it will be readily understood.however, equation in View of the following descri tive ma 1 ..r and thedrawingsf 'fhot some aturesom in /en on may be cmplo without a toid escqoiing use of other 'eatures. It shook) be remarked, however, thatwhile [he (liontrullill valve mechanism may actffiidirectl contro l thesupply of steam or other heating iluid to the raduitor or the escape ofair, steam, wator of condensation etc. from the radiator or may controljointly thcsupnly ofgheatin fluid to, and its escape from the radiator,

prefer to employ in such valve mechanism a valves such as fluid motorvalves. whichare either shut ti ht or wide open, arrangements regard. itas essential that .Ll'Ts controlling valves shall be throttling valvesin order to obtain a gradual variation of the rateof flow of the heatingfluid 4 y The various features of novelty ifwhich characterize myinvention are poiated o with particu and fornu apartofthisspecificatione F0 a better on erstanding m "nvention a. some ofthe advantages ossessed l; itand some of the days in whic i it may 1)carried out, however, reference should be had to the accompanyingdrawings ,and descri tiiveescribed somewhat in detail variousembodiments of my invention.

In the drawings, Fi urc l is a diagrammatic regresentation o? a heatingsystem in which t e thermostatic actuated control valve is located inthe, heating fluid supply pipe; Fig. 2 is a view similar to Fi 1 showmga system in which the centred valve is located in the low ressureconduit leading away from the radiator; Fig. 3 is a view similar to Fig.1 showin a system in which the controlling-valve mec ianism controls theconnection between tl: supply pipe and the radiator and also between theradiator and the low pressure return conduit; Fig. 4 is a view similarto Fig. l of a system in whic the thermostatic actuated valve isemployed to control the escape of air from the radiator. This view alsoshows thermostatically controlled means lb:- regulating the flow of thetheme agent acting on the thermostatic mechanism for the controllingvalve; is His 0. view similar to Fig. I showinga. dill'erority in theclaims annexed toand in some i throttling valve or valves in preferenceto escape of the heating ent arrangement for acting. thermally on theactuating mechanism of the control valve; Fi 6 is a view similar to Fig.2, but showing a different arrangement for acting thermally on theactuating mechanism of the control valve; Fig. 7 is a view similar toFig. 3, but showin a different arrangement for acting thermaly on theactuating mechanism of the controlling valve mechanism; Fig. 8 is a viewsimilar to Fig. 4 showing a system in which the controlling valveregulates the escape of air from the radiator, but showing anarrangement for acting thermally on the valve actuating mechanism of thecontrolling valve different from that of Fig. 4. Fig. 9 is an elevation,partly in section, illustrating the thermostatic valve controlling thesuply of the heating fluid to the radiator shown in Fig. 1. Fig. 10 is asectional elevation of the thermostatic valve controlling the connection between the radiator shown in Fig. 2 and the low pressure returnpi e. Fig. 11 is a sectional elevation of the t iiermostatic valvemechanism em loyed in controlling the supply of the heating fluid to andits escape from the radiator shown in Fig. 3. Fig. 12 is a sectionalelevation of the thermostatic valve mechanism for controlling the escapeof air from the radiator shown in Fig. 4. Fig. 13 is a diagrammaticrepresentation of the thermostatically controlled motor operated fanarrangement for varying the flow of the fluid acting thermally on thethermostatic mechanism of the valve shown by Fig. 12. Fig. 14 is asectional elevation of the thermostatic valve for controlling the supplyof steam to the radiator shown in Fig. 5. Fig. 15 is a sectionalelevation of the thermostatic ilot valve employed with the radiators sown in Fig. 5 to 8 inclusive. Fig. 16 is a sectional elevation of thethermostatically actuated valve for controlling the fluid from theradiator shovm in Fig. 6. Fig. 17 is a sectional elevation of thethermostatic valve mechanism for controlling the supply of heating fluidto and its escape from the radiator shown in Fig. 7 and Fig. 18 is asectional elevation of the thermostatic valve for controlling the escapeof air from the radiator shown in Fig. 8.

Like reference symbols apply to like parts throughout the dra ings.

In all the various forms of my invention, A indicates a radiator orheating unit; B a pipe or conduit leading to the radiator from the steamor other heating fluid supply conduit; and B the low pressure returnpipe or conduit leadin from the radiator to a low pressure cham or Vreceiving the water of condensation, air or steam etc. discharged fromthe radiator.

In the construction illustrated in Fig. 1, the ipe B leads to the upperend of the con trol ing valve B. This valve, see Fig. 9, comprises anouter surrounding part B preferably of a material having a lowcoefiieient of expansion, such as iron, having valve arts B and Bsecured to its ends, and an inner part B, of a material having a highcoefficient of expansion, such as brass. The inner member is fastened atone end to the outer member, or some part associated therewith, and,preferably, in such a manner as to permit relative adjustment of theparts B and B, as b fastening the part B to a nut B adjustabiy connectedto the valve part B. The inner or expandin member B is connected to ahollow piston working in a casim or surrounding part B secured in thepart B". The piston B is provided with ports or openings B cooperatingwith ports or openings B in the casing B The positions of ports B and B"are adjusted with respect to each other in accordance with theconditions met. \Vhen the ports B and B are in partial or completeregister with each other, steam or other heating fiuid,from the pipe Basses through the ports into the coupling leading to the radiator. A conduit B leads from the external atmosphere to the lower end of the valveand admits air from the external atmos here into the chamber or spacebetween t e members B and B. The air thus admitted to this chamberescapes from the valve through the open ended conduit B. The conduit Bis preferably arranged at its end so as to surround or be associatedwith the supply pipe B".'

By this arrangement the heat from the supply pipe tends to produce anaspirating effect, which assists in drawing the external air through thecontrolling valve. The operation of this form of my invention is asfollows: The parts are so adjusted that in normal operation the ports Band B are in partial register, the amount which the ports overlap beinsufficient to allow heating fluid to pass to t e radiator at a rate justfast enough to kee the temperature of the apartment to be eated at thedesired point. Upon a fall in external temperature, more heating fluidmust be admitted to the radiator in order to maintain the desiredapartment temperature. This is automatically taken care of by thecontraction of the member B resultin from the lower temperature of theair admitted to the valve through the pipe 13. The contraction of themember B" of course results in bringing the ports B and B more nearlyinto complete register and thereby increases the flow of heating fluidto the radiator. When the external temperature rises, a reverse actiontakes place. It will thus be seen that the heating effect of theradiator shown in Fig. 1 is automatically varied in response tovariations in the external atmosphere to keep the temperature of theapartment uniform and the cause which tends to produce a fluctuation inthe temperature of the apartment is thus utilized to prevent suchfluctuation. A further rc ulation of the radiator shown in Fi I may behad through-the valve B contro ling the connection between the radiatorand the low pressure return pi e. If water of condensation or other reatively cold heating fluid is allowed to accumulate in the radiator, itsheating effect is, of course, diminished.

In the arrangement shown in Fig. 2, the controlling valve C regulatesthe escape from the radiator of water of condensation or otherrelatively cold fluid. The valve C, (Fig. 10) is practically identicalin Ian and construction with the valve 13, tic parts being inverted,however.

When the ports B and B are in partial or complete register, dischargeconduit B", directly connected to the radiator, is placed incommunication with the conduit B. Any water or relatively cold fluidwhich may have accumulated in the radiator, then passes into the returnpipe B to make place for live steam or other hot fluid. The operation ofthe valve 0 is controlled by the external air passing from the conduitinto the member B from which it escapes through ports B and B.

In the arrangement shown in Fig. 3, the controlling valve mechanism D,shown in detail in Fig. 11, governs the passage of live steam, or otherheating fluid, to the radiator and also the escape of the water ofcondensation, or the like. The valve D comprises parts B, B, B, B and B"which may be practically identical with those shown in Fig. 9. Thepiston B has adjustably secured to it the upper end of the member Dwhich is axially disposed in the member B and pro jec ts from the lowerend thereof. The member D is referably of a material having a relativelyow coefiicient of expansion. To the lower end of the member D is secureda piston D sliding in a casing D secured in the part B". The piston Dand easing D are provided with ports D and D resfpectively which arebrought into and out o more or less complete registry with each other togov cm the connection of the radiator discharge pipe B" to the pi e B.With the construction described, t 10 entrance of the heating fluid tothe radiator and its escape therefrom are simultaneously controlled. Tofacilitate adjustment of the member D relative to the member 13 Iprovide the sup ly conduit B with a removable plu D t rough which toolsmay be inserted 'or entering the slots D", or the like, on the piston Band the slot 1) in the upper end of the threaded plug D secured to theupper end of the member D and threaded into iston B. It will be observedthat the col air from the conduit B" asses into the s ace between themembers 2 and B throng the ports D and also into the space between themembers I) and B from the upper end of which it esca 105 through orts D,the expansihlc member B thus laving its inner and outer sides swe t bystreams of cold air.

Tie radiator shown in Fig. 4 is provided with a valve E, Fi 12, forcontrolling the escape of air from 1; ac radiator. The valve isconnected to the radiator by the hollow part 15*. The air from theradiator passes through the ports E and E into the member B and thenceto the return pipe. The air from the external atmosphere passes into thelower end of the member B through the conduit B and esca es from theupper end of the member B t lrough the ports 1*). With the form of myinvention shown in Fig. 4, I have provided means for varying the flow ofair rom the external atmosphere to the valve in response to variationsin the temperature of the apartment to be heated. The )artieular meansdisclosed for producing this effect comprises a fan havin its outlet ortconnected to the conduit 33" and its inlet port connected to the conduitB. The fan is operated by an electric motor F the speed of which variesin response to variations in the temperature of the apartment heated. InFig. 13 the speed controlling means for the motor are showndiagrammatically to consist of an expansive member F provided with acontact piece F moving over contacts F connected by electric resistancesF \Vhcn the temperature in the a artment falls, the member F contracts,an contact F shortcircuits some of the resistances F 5 which are in themotor circuit. This speeds up the mo tor and increases the air from theexternal atmosphere forced to flow by the member B This of coursehastens the movement of the port E relative to the port E and also controls the extent of movement, since the port B receives heat byconduction from the radiator, and also by radiation from the radiatorand the room atmosphere; and its resultant temperature is influenced,therefore, not only by the tem erature of the stream of air entering theva ve through the conduit 13 to act on the thermostatic valve actuationmechanism, but also by the rate of flow of this stream of air. It is, ofcourse, obvious that this or other means may be employed for varying theflow of air from the external atmosphere into the valves B, C and D.

The Valve G, Fig. 14, which controls the sup ly of heating fluid to theradiator shown in ig. 5, is essentially the same in general constructionas the valve B, of Figs. I and 9. The means for supplying the temerature chan ing fluid to the space between t 1e members and B differmateriall however. In this form of my invention, a t \ermostatie pilotvalve K, see Fig. 15, is employed. The valve K comprises an outertubular member K of a material having a relatively high coeflieient ofexpansion, in connection with a member K having a relative] lowcoeflicient of expansion. The u er on of the member K is secured to aplug {3 adjustably screwed into the upper end of the member K. The lowerend of the member K supports a piston K sliding in a tubular casing Ksecured in a valve part K". The valve part K is rovided with u er andlower valve cham ers K and K I hrts K" and K formed in the casing K inconjunction with ports K and K formed in the piston K are employed forinterchangeably placing the interior of the hollow )iston K incommunication with the valve chambers K and K. When the temperature ofthe apartment is below the normal apartment temperature, the ports K andK are brought into more or less complete registration. Similarly, whenthe spartment temperature rises above a pre etermined point, the ports Kand K are brought into more or less complete registration. A conduit Lleads from the valve chamber K to a conduit L, which is in communicationwith the u per end of the valve G. The conduit L inc udes a coil Llocated without the apartment and subject to the temperature of theexternal atmosphere. The valve chamber K is connected to the conduit Lby a conduit M, a portion of which asses in close proximity to theradiator. he lower end of the hollow piston 'K is connected by a conduitN with a source of air under pressure, such as the ump 0. When thethermostatic valve K ias its ports, K and K brought into register,compressed air from the ump O forces air into the up or end of the valveG. This air, which is coo ed by passing through the coil L, flowsbetween the members B and B, contracts the latter and brings the ports Band B into more or less complete register, thus admittin live steam orother heating fluid to the ra later. When, thereafter, the temperatureof the a artment rises sufficiently, the communication between theconduit M and the valve chamber K is closed by the movement of thepiston K resulting from the expansion of the member K. This of itselfallows the member B to warm up and shut off the supply of the heatinfluid to the radiator. If the temerature oi the apartment continues torise, liowever, the expansion of the member K brings the ports K? and Kinto register and air is then forced into the up or end of the valve Gfrom the conduit M. his air, being heated by its proximity to theradiator, acts very rapidly upon the valve G to cause it to cut oilconnection between the supply conduit B and the radiator. With thisarrangement it will be observed that the main control valve G has itsthermostatic actuating mechanism operated ,upon to 0 en connectionbetween the radiator and t 1e source of heating fluid by a'stream ofcold air, the flow of which is controlled by the temperature of theapartmentheated, thus rapidly opening the controlling v'alve whennecessa As both of the valves G and K are t irottle valves, the increasein heating eflect of the radiator is efl'ected not only by the amount ofvariation of the room temperature from the normal, but also by thetemperature of the external atmosphere the effect of the stream of coldair on the member 13 being a function of the amount of air flowing andits temperature. The provision of the hot air supply conduit M permitsof a very rapid closing of the main valve when the temperature risesabove a predetermined point.

The valve H, see Fig. 16, which controls the escape of water ofcondensation of other cooled heating fluid from the radiator A of Fig. 6is practically the same in construction as the valve C, but differs,however, in the fact that the fluid for action thermally on the member Bpasses from a chamber H at the upper end 0 the valve into the interiorof the member B and is drawn therefrom into the return pipe B through aport II formed in the upper end of the hollow piston B. In this form ofmy invention, the conduits L and M are connected by a coupling L leadingto the chamber H, as in the construction of Fig. 5. The conduit N andpump 0 are dispensed with, however, air being drawn through the hollowmember B into the return pipe B from the conduits L and M whenever thevariations in the apartment temperature bring the ports K and K or K" orK (see Fig. 15) into register and thus place the pipes L or M incommunication with the interior of the hollow piston K which in thisform of my invetnion is open to the atmosphere. With this form of myinvention, a positive flow of air actingthermally on the actuatingmechanism of the main valveis obtained in a very simple manner by theconnection described to the return pipe thus obtaining all theadvantages of the construction shown in Fig. 5 while eliminating the extra conduits and source of compressed air.

In the construction shown in Fig. 7, the valve I, Fig. 17, employed forcontrolling the supply to and escape from the radiator of the heatinfluid, is practically identical with the valve of Figs. 3 and 11. Thespaces into which the air acting on the thermostatic actuating mechanismof this valve passes, are connected at their lower ends to the returnpipe B by the connection I. Air is supplied to the upper end of thesespaces from a conduit P which is connected to the lower end of thehollow piston K. The valve chamber K has connected to a conduit Lleading from the external atmosphere and the valve chamber K hasconnected to it a conduit M, the other end of which is open and aportion of which is in proximity to the radiator. In this form of myinvention, cold air flows to the actuating mechanism of the valve Ithrough the conduits L and P and warm air flows to the valve through theconduits M and P.

In the form of my invention shown in Fig. 8, the main controlling valveJ, which con trols the escape of" air from the radiator is practicallyidentical with the valve E of Figs. 4 and I2, difl'ering from thatvalve, however, in that the controlling air is delivered b the conduit Ito the chamber J in communication with the interior of the member B, thelower end of which is in communication with the return pipe B" throughthe port J. Hot or cold air is supplied to the chamber J through theconduit Pin the same manner as in the construction shown in Fig. 7.

\Vhile I have hereinbeiore described somewhat in detail a number offorms in which my invention may be embodied, it will be readilyunderstood by all those skilled in the art that changes may be made inthe forms disclosed without depart from the spirit of my invention andarticularly that some features of my invention may be employed without acorrespond' use of others and that the various novel eatures disclosedmay be employed in different arrangements from those set forth.

The novel methods of controlling the heating 'ca aeity of heat radiatingdevices, disclosed ut not claimed herein, form the subject matter of myprior applications, serial numbers 158,039 and 158,040, filed on the20th day of May, 1903, which disclose the a paratus forming thesubject-matter of tie present application.

Having now described my invention, What I claim as new and desire tosecure by Letters Patent is 1. In a heating system, a radiator, aheating fluid su ply conduit and slow ressure return con ult connectedto said re 'ator, a valve controlling the flow' of the heating fluidthrough the radiator and thermostatic actuating mechanism for the valvehaving a chamber or assa e in communication with a source of air aninclud' a member having a relatively high coeflicient of expansion inproximity to said chamber or passage and a conduit leading from saidchamber to said low pressure return conduit.

2. In combination, a radiator for heating an apartment, 9. throttlingvalve controlling the flow of a heating fluid thercthrou h, thermostaticactuating mechanism for t is valve, means for subjecting said mechanismto the action of a thermal agent varying in temperature with theexternal atmos row and means for varying the influence 0 said thermalagent on said mechanism in response to variations in the temperature oft ie a artment to be heated.

3. n a heating system, a radiator for heating an apartment, a heatingfluid supply conduit and a low pressgre 'rcturmgonduit connected to saidradiator, a valve controllin the flow of heating fluid through the rariator, thermostatic actuating mechanism for the valve having a chamberor semi e and including a member having a reliitively high coeflicientof expansion in proximity to said chamber or passa 'e, means responsiveto the temperature of t is apartment heated for opening and 'closiu saidchamber to a source of air and a con uit leading from said chamber orpassage to said low pressure re turn conduit.

4. In combination, a radiator for heating an apartment, a throttlimvalve controlling the flow of the heating lluid throu h said radiator,thermostatic actuating mec anism for the valve, means for causing astream of a fluid thermal agent to flow past, against and by saidmechanism to change the tempera ture of the latter in passing, and meansfor varying the llow of said stream without cha ing its direction inresponse to variations in the temperature of the apartment to be heated.

5. In combination, a radiator, a throttlin valve controllin the flow ofheating flui through said ra iator, thermostatic actuating mechanism forthe valve, means for causmg a stream of air varying in temperature withthe external atmosphere to How against and'by said actuating mechanismand means responsive to the temperature of the apartment to be heatedfor controlling said stream.

6. In combination, a radiator, a source of heating fluid, a conduitleading from said source to said radiator, 11. low pressure returnconduit leading away from the radiator, a valve control] the flow of theheating fluid through tiie radiator, thermostatic actuating mechanismfor said valve, including a chamber or passage, a conduit leading fromsaid chamber to said return conduit and'a conduit leading to saidchamber from a source of supily of a fluid thermal agent for acting onsai thermostatic actuating mechanism.

7. In combination, a radiator for heating an apartment, a source ofheating fluid, a conduit leading from said source to said radi ator, alow ressure return conduit leading away from t ic radiator, a valvecontrolling the flow of the heating fluid through the radiator,thermostatic actuating mechanism for said valve includin a chamber orpassage, a conduit leading om said chamber to said return conduit, aconduit leading to said chamber from a source of supply of a fiuid agentfor acting thermally on sai thermostatic actuating mechanism, and meansresponsive to the'temperature of the apartmeet to be heated for varyingthe flow of fluid through said chamber.

8. In combination, a radiator for heating theiternal atm an apartment, asource of heating fluid, a conduit leading from said source to saidradiator, a low pressure return conduit leading away from the radiator,a valve cent 01- ling the flow of the heating fluid through theradiator, thermostatic actuating mechanism for said valve including achamber or passage, a conduit leading from said chamber to said returnconduit, a conduit leading to said chamber from a source of supply of afluid agent for acting thermally on said thermostatic actuatingmechanism, and a thermostatic ilot valve responsive to the temperatureof the apartment to be heated for controlling the flow through saidchamber.

9. in combination, a radiator, a source of heating fluid, a conduitleading from the source to the radiator, a low pressure return conduitleading away from the radiator, a valve controlling the How of theheating fluid through said radiator, thermostatic actuating mechanismfor said valve, including a chamber or passage, a conduit leading tosaid chamber from a source of air varying in temperature with theexternal atmosphere for acting thermally on said thermostatic actuatingmechanism, and a conduit leading from said chamber to said returnconduit.

10. In combination, a radiator for heating an apartment, a source ofheating fluid, a conduit leading from the source to the radiator, a lowpressure'return conduit leading away from the radiator, a valvecontrolling the flow of the heating fluid through said radiator,thermostatic actuating mechanism for said valve, including a chamber orpassage, a conduit leading to said chamber from a source of gin temerature with here fifi actlng thermally on saidthermostatic actuatingmechanism, a conduit leading from said chamber to said return conduit,and means for varying the flow of air through said chamber in responseto variations in temperature of the apartment to be heated.

11. In combination, a radiator for heating an apartment, a source ofheating fluid, a conduit leading from the source to the radiator, a lowressure return conduit leading away from t i'e radiator, a valvecontrolling the flow of the heating fluid through said radiator,thermostatic actuating mechanism for said valve, including a chamber orpassage, a conduit leading to said chamber from a source of air varyingin temperature with the external atmosphere for acting thermally on saidthermostatic actuating mechanism,

a conduit leading from said chamber to said return conduit and athermostatic pilot valve responsive to the temperature of the apartmentto be heated for varying the flow to said chamber from said source.

12. In combination, a steam heating device and means for supplying steamthereto, a low pressure return pipe, a valve connectmg said pipe to saidradiator and controlling the escape from the radiator to the )ipe ofsteam and water of condensation, thernio static actuating mechanism forthe valve, a thermostatic pilot valve responsive to the temperature ofthe apartment heated, and means governed by it for causing air drawnfrom the external atmosphere in an amount varying in a predeterminedmanner in accordance with variations in the temperature of the apartmentheated to flow through or by said actuating mechanism to act thermallythereon.

'13. In combination, a radiator, means for supplying steam thereto, alow pressure return pipe connected to said radiator, a valve in saidpipe controlling the passage of steam and water of condensation from theradiator through the return pipe, thermostatic actuating mechanism forthe valve including a chamber, a passage leading from said chamber tothe return pipe, a conduit for supplying air varyin in temperature withthe external atmosp ere to said chamber to act thermally on saidmechanism and thermo statically controlled means for varying the flow ofsaid air through said conduit in resgonse to variations 1n thetemperature of t e apartment to be heated.

14. In combination, a radiator, means for supplying steam thereto, a lowpressure return pipe, a throttling valve for'opening and closingconnection between the radiator. and the return pipe, thermostaticactuating mechanism for the valve, including a chamber in communicationwith the return pipe, a conduit leading to said chamber from theexternal atmosphere, a valve controllin the flow of air through saidconduit to said chamber to act thermally on said mechanism, and meansactuating said valve to vary the flow of air from the externalatmosphere through the conduit as the temperature of the apartment to beheated falls and rises.

HARRY C. MALLORY.

